The process of vibration welding involves the controlled application of high frequency vibration energy to a clamped work piece. Surface friction generates heat at a weld interface, which ultimately softens and bonds adjacent work piece surfaces at the interface. The efficiency, consistency, and long term reliability/durability of a vibration welded assembly depends largely on the welding tools and control methodology used to form the various welds.
Various closed-loop parameter-based control techniques are typically applied during a vibration welding process to keep certain weld parameters within calibrated limits. This approach can produce reasonably consistent welding parameters over time. However, stable welding process parameters may still fail to produce welds of a consistently high quality. In addition, external factors such as material quality can also impact weld quality. Moreover, a premature failure of just one weld can affect the performance of a welded system. It is therefore common practice in such systems to determine weld integrity by visual inspection and a laborious process known as picking, wherein each of the formed welds is physically tested by an operator using a picking tool.